HiPIMS技术低温沉积CrN薄膜结构及性能研究

目的 实现性能优异的CrN薄膜在低温沉积条件下的可控制备。方法 利用高功率脉冲磁控溅射技术(HiPIMS)，通过调控脉冲放电波形(可调控脉冲放电模式-MPP、双极脉冲放电模式-BPH)制备了系列低温沉积工艺下的CrN薄膜。选用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、原子力显微镜(AFM)、纳米硬度测试仪及球盘摩擦试验仪表征了CrN薄膜的组织结构、微观形貌、摩擦学性能。结果 相对于传统的直流磁控溅射技术(DCMS)，HiPIMS具备高溅射材料离化率，偏压作用下产生的荷能离子对成膜表面的持续轰击作用，有效提升了低温沉积条件下成膜粒子的表面迁移能，显著抑制了贯穿柱状晶的连续生长，达到了细化晶粒，改善薄膜致密性的目的。BPH模式下沉积的薄膜表面光滑致密，表面粗糙度可达4.6 nm。细晶强化作用及薄膜致密性提升使得BPH模式下制备的CrN薄膜硬度最高，可达(15.6±0.8) GPa。此外，BPH模式下沉积的CrN薄膜具备最为优异的摩擦学性能，摩擦系数低(~0.3)且运行平稳，并且在高速及重载作用下，仍能表现出优异的摩擦磨损性能。结论 HiPIMS技术中的双极脉冲放电模式可显著提升沉积粒子表面迁移能，提升CrN薄膜沉积反应动力学过程，实现低温条件下性能优异的CrN薄膜的可控制备。

Microstructure and Properties of CrN Films Prepared by HiPIMS at Low Temperature

The work aims to achieve the controlling preparation of high-performance CrN films at low temperature. High power impulse magnetron sputtering (HiPIMS) technique was used to prepare CrN films at low temperature parameters by regulating the HiPIMS discharge mode (modulated pulsed power mode-MPP and bipolar pulse power mode-BPH). XRD, FESEM, AFM, nanohardness tester and ball on disk tribological tester were used to characterize the microstructure, morphology, mechanical and tribological properties of CrN films. Compared with DCMS, HiPIMS could produce high degree of ionization of the sputtered materials, which significantly increased the ion bambordment on the growing surface by the optimal substrate bias. With enhancing ion bombardment, the surface migration energy of the adatoms increased sharply, which inhibited the growth of transgranular fracture significantly, thus achieving the refinement of grain size and improving the density of films. The surface of CrN films deposited in BPH mode showed smooth and denser structure, with the surface roughness as low as 4.6 nm. Due to the improvement of grain refinement and density, the CrN films prepared in BPH mode obtained the highest hardness of (15.6±0.8) GPa. In addition, the CrN films prepared in BPH mode showed the most excellent tribological behavior, with a lower COF of about 0.3, the films were stable and could still show excellent tribological properties under the high-speed and heavy-duty cycle conditions. The BPH mode in HiPIMS can significantly increase the surface migration energy of adatoms, promote the film growth dynamics process and achieve the controlling preparation of CrN films with excellent performance at low temperature.